arXiv subjects

N. I. Petrov

Publications and source records attributed to N. I. Petrov.

10 recordsLinked to original sources

arXiv2025

Mixed cat states at low purity of light

Pure states are usually used to observe quantum phenomena. In this study, we show that a quantum superposition of spatially displaced mixed cat states can be generated within an optical waveguide via nonparaxial unitary evolution of the initial low coherence (low purity) light beam. It is shown that highly mixed Schrodinger cat states can be observed at a well-defined propagation distance. The importance of the long-term decoherence and recoherence of the original wave packet in observing the mixed cat states is demonstrated. The Heisenberg and Schrodinger-Robertson uncertainty relations for mixed cat states are evaluated. We have demonstrated the feasibility of our method using accurate numerical simulations for the parameters of the source and optical waveguide available in practice.

quant-ph↗

arXiv2024

Direct observation of the enhanced photonic spin Hall effect in a subwavelength grating supporting surface plasmon resonance

The photonic spin Hall effect (PSHE) in surface plasmon resonance (SPR) structures has great potential for various polarization-sensitive applications and devices. Here, using optical weak measurement, we observe spin-dependent and spin-independent angular shifts of the reflected beam, enhanced by SPR in a subwavelength nickel grating. An enhanced in-plane photonic spin Hall effect manifested in the angular splitting of circularly polarized photons with opposite helicity signs is demonstrated. We theoretically and experimentally demonstrate that angular in-plane shifts can be changed from spin-independent (Goos-Hänchen shift) to spin-dependent (PSHE) when the incident beam polarization state changes. The SPR-induced depolarization of light and the mixing of polarization states are detected. High purity of spin separation and a high degree of circular polarization are achieved with an optimal polarization state (preselection angle) and a resonance angle of incidence. The spineless spatial separation of two orthogonal components of the field with diagonal linear polarizations is demonstrated.

physics.optics↗

arXiv2024

Lightning as a natural accelerator of relativistic particles and a source of synchrotron radiation

A physical model of the formation of a vortex current in a plasma channel of lightning discharges due to the anomalous Hall effect caused by relativistic spin-orbit interaction phenomenon is proposed. The existence of fast electromagnetic surface plasmon waves propagating along the lightning discharge channel at a speed close to the speed of light in vacuum is shown. The spin properties of electrons become important at relativistic velocities, so the spin-orbit coupling arises as an effective magnetic force acting on the spin of an electron, leading to the formation of a spin-induced vortex current in the absence of an external magnetic field. This makes it possible to consider the lightning discharge channel as a charged particle accelerator that generates microwave, X-ray, gamma-ray and RF emissions by a current pulse moving along a helical trajectory via synchrotron and cyclotron radiation mechanisms. The proposed theoretical model of the formation of a spin-induced vortex current in the lightning plasma channel is consistent with observations of lightning and spark discharges.

physics.plasm-ph↗

arXiv2023

Multispectral narrowband frustrated total internal reflection filter with inclusions of plasmonic nanoparticles

A spatial-frequency thin-film filter with inclusions of nanoparticles operating in the visible range of the spectrum is investigated. The effect of nanoparticles embedded in the central and lateral layers of the frustrated total internal reflection filter on the spectral characteristics, taking into account the frequency dispersion, is investigated. It is shown that plasmonic effects cause splitting of the filter bandwidth into a set of narrow-band spectral lines and angular splitting of the incident beam into a set of output beams.

physics.optics↗

arXiv2020

Modeling of the final jump phase of a positive lightning leader

Behavior of the potential and electric field intensity at the front of a lightning leader channel taking into account the influence of space charges injected by the streamers is investigated theoretically. Analytical solutions of Poisson equation are found for different laws of charge density distribution in the streamer zone. Influence of the streamer zone parameters on the formation of final jump phase of a leader is investigated.

physics.plasm-ph↗

arXiv2019

Electromagnetic fields created by the lightning leader channel in the final jump phase

The dependences between the parameters of the Lightning discharge in the leader phase and the return stroke phase are obtained. It is shown that the peak values of the electric field created by lightning are determined by the parameters of the streamer zone of the leader at the final jump phase. It is shown that a large peak value and the steepness of the lightning return stroke current are generated in the final jump phase.

physics.plasm-ph↗

arXiv2019

Non-invariance of the speed of light in free-space

A plane monochromatic wave propagates in vacuum at the velocity of c. However, wave packets limited in space and time are used to transmit energy and information. Here it has been shown based on the wave approach that the on-axis part of the pulsed beams propagates in free space at a variable speed, exhibiting both subluminal and superluminal behaviours in the region close to the source, and their velocity approaches the value of c with distance. Although the pulse can travel over small distances faster than the speed of light in vacuum, the average on-axis velocity, which is estimated by the arrival time of the pulse at distances z >> ld (ld is the Rayleigh diffraction range) and z > ct (t is the pulse width) is less than c. The total pulse beam propagates at a constant subluminal velocity through the whole distance. The mutual influence of the spatial distribution of radiation and temporal shape of the pulse during nonparaxial propagation in vacuum is studied. It is found that the decrease in the width of the incident beam and the increase in the central wavelength of the pulse lead to a decrease in the propagation velocity of the wave packet. It is shown that the velocities of the Bessel-Gauss and Laguerre-Gauss pulsed beams decrease with increasing orbital angular momentum (OAM). The results obtained are in good agreement with subluminal and superluminal measurements in free space.

physics.optics↗

arXiv2019

Spectral observations of X Persei: Connection between H-alpha and X-ray emission

We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999 - 2018. Using new and published data, we found that during "disc-rise" the expansion velocity of the circumstellar disc is 0.4 - 0.7 km/s. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the disc by resonances 10:1, 3:1, and 2:1, while the maximum disc size is larger than the Roche lobe of the primary and smaller than the closest approach of the neutron star. We find correlation between equivalent width of H-alpha emission line ($Wα$) and the X-ray flux, which is visible when $15 \: Å\: < Wα\le 40 \: Å$. The correlation is probably due to wind Roche lobe overflow.

astro-ph.SR↗

arXiv2017

Observations and light curve solutions of the W UMa binaries V796 Cep, V797 Cep, CSS J015341.9+381641 and NSVS 3853195

Photometric observations in Sloan g' and i' bands of four W UMa binaries, V796 Cep, V797 Cep, CSS J015341.9+381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1+382805 and NSVS 3853195 are the same star. We determined the initial epochs T_{0} of all targets and improved the period of NSVS 3853195. The light curve solutions of our data revealed that the components of each target are almost the same in mass, temperature, radius and luminosity. The stellar components are of G and K spectral types and undergo partial eclipses. All systems have barely-overcontact configurations and belong to H subtype W UMa binaries. We established that the relation between the luminosity ratio l_{2}/l_{1} and mass ratio q of our targets is approximately l_{2}/l_{1} = q^{1.5}.

astro-ph.SR↗

arXiv2011

Left-right asymmetry in an optical nanofiber

Symmetry breaking effect for left- and right-handed circularly polarized light beams propagating in a rotationally symmetric graded-index optical fiber is presented. It is shown that a left-right asymmetry manifested as an unequal transmission for opposite circular polarizations occurs due to spin-to-spin angular momentum conversion caused by tensor interaction.

physics.optics↗